Erythrocyte swelling and membrane hole formation in hypotonic media as studied by conductometry.

Hypoosmotic swelling of erythrocytes and the formation of membrane holes were studied by measuring the dc conductance (G). In accordance with the theoretical predictions, these processes are manifested by a decrease in G followed by its increase. Thus, unlike the conventional osmotic fragility test, the proposed methodological approach allows investigations of both the kinetics of swelling and the erythrocyte fragility.

The mechanism of the polymer-induced drag reduction in blood.

Literature reports provide evidence that nanomolar concentrations of spaghetti-like, high molecular weight polymers decrease the hydrodynamic resistance of blood thereby improving impaired blood circulation. It has been suggested that the polymer-induced drag reduction is caused by the corralling of red blood cells (RBCs) among extended macromolecules aligned in the flow direction. This mechanism predicts that drag-reducing polymers must affect the conductivity of completely dispersed blood, time-dependent and steady state structural organization of aggregated RBCs at rest.

A novel approach for assessments of erythrocyte sedimentation rate.

Introduction: Previous studies have shown that the dispersed phase of sedimenting blood undergoes dramatic structural changes: Discrete red blood cell (RBC) aggregates formed shortly after a settling tube is filled with blood are combined into a continuous network followed by its collapse via the formation of plasma channels, and finally, the collapsed network is dispersed into individual fragments. Based on this scheme of structural transformation, a novel approach for assessments of erythrocyte sedimentation is suggested.

Methods: Information about erythrocyte sedimentation is extracted from time records of the blood conductivity measured after a dispersion of RBC network into individual fragments.

The effect of the prior flow velocity on the structural organization of aggregated erythrocytes in the quiescent blood.

Usually, investigations of erythrocyte aggregation at rest are focused on effects of the strength of erythrocyte-erythrocyte attractive interactions and the volume fraction of the cells, whereas the role of prior flow velocity has not been thoroughly investigated. The aim of this study is to fill this gap. The main conclusions extracted from time records of the complex admittance of blood are as follows: (1) Dispersion of blood in a prior flow into discrete aggregates increases the mesh size of network, which, as has been recently shown, is formed in the quiescent blood.

The mechanism of erythrocyte sedimentation. Part 1: Channeling in sedimenting blood.

Despite extensive efforts to elucidate the mechanism of erythrocyte sedimentation, the understanding of this mechanism still remains obscure. In attempt to clarify this issue, we studied the effect of hematocrit (Hct) on the complex admittance of quiescent blood measured at different axial positions of the 2 mm x 2 mm cross-section chambers. It was found that after the aggregation process is completed, the admittance reveals delayed changes caused by the formation of cell-free zones within the settling dispersed phase.